Chlamydia trachomatis (C. trachomatis) is a prokaryote. This organism includes the A, B, Ba, C, D, E, F, G, H, I, J, K, LI, LII, and LIII serotypes. C. trachomatis is the causative agent of trachoma (which is the greatest single cause of blindness), inclusion conjunctivitis, infant pneumonitis, urethritis and lymphogranuloma venereum. Diagnosis and detection of this organism is often on the basis of the pathologic or clinical findings and may be confirmed by isolation and staining techniques.
C. trachomatis includes a cryptic plasmid which is approximately 7.5 kb in size and is present in multiple copies in the organism. The presence of multiple copies makes this plasmid a good target for diagnostic purposes for assays using nucleic acid amplification techniques. Accordingly, many diagnostic companies currently manufacture assays for detecting C. trachomatis that uses the organism's cryptic plasmid as a target.
However, there have been reports of C. trachomatis lacking the cryptic plasmid and such strains have been isolated from patients. Additionally, there have been reports of a variant strain of C. trachomatis harboring a cryptic plasmid with a 377 base pair deletion, the area of which is targeted by assays used to detect C. trachomatis; assays that target this area would therefore yield a false-negative result. Thus, new diagnostic techniques aimed at more reliably and accurately detecting C. trachomatis are desired.